Wrap-around severe splash seal

ABSTRACT

A wrap-around interlocked labyrinth seal adapted to be mounted upon a rotating shaft, having a rotor and a stator. A flange positioned on the stator completely encircles the rotating shaft. The stator is interlocked by positioning a cover of the stator within a radial opening of the rotor and interlocking the cover with an enclosure member of the rotor. One embodiment of the seal includes an interlocking member as part of the cover. The interlocking member interlocks with a flange of the rotor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.09/200,152, filed Nov. 25, 1998, the entire disclosure of which isincorporated herein by reference, and claims priority therefrom.

FIELD OF THE INVENTION

The present invention relates to a device for providing a static and adynamic seal between a rotatable shaft and a housing. In particular, thepresent invention relates to a seal device for inhibiting oil fromleaking out of a housing and/or for inhibiting contaminants fromtraveling into the housing in severe splash conditions.

BACKGROUND

Prior art devices for sealing a rotating shaft are disclosed in U.S.Pat. No. 4,022,479 (Orlowski). Seal devices of this type may be used toinhibit oil from escaping out of a bearing housing and/or to inhibitcontaminants from working their way into the housing. The prior artdevices are formed of at least two ring-shaped members that rotate withrespect to each other when the shaft is rotated. One of the members isfixed to the housing and does not rotate. The other member rotates withthe rotating shaft.

The two ring members should be located very close together, particularlywhen the seal device is used to isolate the bearing from smallparticulate contaminants. Even small quantities of such contaminants arecapable of significantly deteriorating the bearing. To inhibit suchcontamination, the two relatively rotatable ring members must be heldtogether very closely, with only a very narrow space therebetween.

The ring members of the Orlowski seal device are connected together by aseparate securing means, not shown in the prior art patent. The ringmembers themselves have no means for establishing and maintaining anarrow spacing therebetween. Therefore, the prior art seal device cannotbe manufactured as a unit with a preset, fixed spacing. The spacingbetween the ring members has to be set when the seal device is installedinto the housing. This leaves room for human error outside the controlof the device manufacturer. In particular, the Orlowski device can beimproperly installed, with the ring members located too far apart toperform satisfactorily. Another problem with the Orlowski device is thatthe ring members may be separated subsequent to installation, forexample by high pressure cleaning spray.

Some prior art references refer to the use of a rotor and a stator, thelatter including a plurality of alternating annular grooves and ridgesand an axial groove. The grooves and ridges catch oil thrown by therotating shaft. The oil then drains by gravity to the axial groove whichallows the oil to travel back into the housing. One such reference, U.S.Pat. No. 5,522,601 (Murphy), refers to a locking labyrinth sealingassembly where a flange on a rotor wraps around and interlocks with aflange on a stator. The Murphy device, however, lacks an air-sideopening and an oil-side opening which is sealed at the rotating shaft,making such a device susceptible to oil leakage in severe splashapplications.

Other prior art references, such as, for example, U.S. Pat. No.4,667,967 (Deuring), U.S. Pat. No. 4,065,136 (Miller) and U.S. Pat. No.3,343,891 (Shipman) refer to sealing devices utilizing two or morepieces. Each of these seal devices lacks an air-side opening and anoil-side opening which is sealed at the rotating shaft. These types ofseal devices may have deficiencies in applications where large amountsof oil can inundate the seals, such as in side-mounted pump bearingframes having double row thrust bearings where the seals are close tothe bearings.

SUMMARY

The problems of the prior art are overcome to a great extent by thepresent invention, which relates to a two-piece, interlocked labyrinthseal and a sealed system including a two-piece, interlocked labyrinthseal. The labyrinth seal includes a rotating member, such as a rotor,and a stationary member, such as a stator. The rotor includes anintermediate portion and an enclosure member surrounding a radialopening, and the stator includes a main body portion with annular ridgesand a cover positioned within the radial opening. The cover interlockswith the enclosure member. One of the annular ridges is adapted torestrict passage of air through the seal when the seal is mounted to ashaft.

The invention also provides a two-piece interlocked labyrinth seal. Theseal includes a rotor with an intermediate portion, an enclosure memberand a flange surrounding a radial opening, and a stator with a main bodyportion, having a plurality of annular ridges, and a cover positionedwithin the radial opening. The cover interlocks with the flange.

The invention further provides a sealed system that includes a rotatableshaft, a housing, and a two-piece interlocked labyrinth seal mounted onthe housing and around the shaft. The seal includes a rotor with anintermediate portion and an enclosure member surrounding a radialopening, and a stator with a main body portion, having a plurality ofannular ridges, and a cover positioned within the radial opening. Thecover interlocks with the enclosure member. One of the annular ridgesrestricts passage of air between the seal and the rotatable shaft.

The invention further provides a sealed system that includes a rotatableshaft, a housing, and a two-piece interlocked labyrinth seal mounted onthe housing and around the shaft. The seal includes a rotor with anintermediate portion, an enclosure member and a flange surrounding aradial opening, and a stator with a main body portion, having aplurality of annular ridges, and a cover positioned within the radialopening. The cover interlocks with the flange.

The foregoing and other advantages and features of the invention will bemore readily understood from the following detailed description of theinvention, which is provided in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a seal device constructed inaccordance with a preferred embodiment of the present invention.

FIG. 2 is a partial cross sectional side view of the seal device of FIG.1, taken along line II—II of FIG. 1, showing the seal device employedwithin a sealed system.

FIG. 3 is a partial cross sectional side view of a seal deviceconstructed in accordance with a second preferred embodiment of thepresent invention.

FIG. 4 is a partial cross sectional side view of a seal deviceconstructed in accordance with a third preferred embodiment of thepresent invention.

FIG. 5 is a partial cross sectional side view of a seal deviceconstructed in accordance with a fourth preferred embodiment of thepresent invention.

FIG. 6 is a partial cross sectional side view of a seal deviceconstructed in accordance with a fifth preferred embodiment of thepresent invention.

FIG. 7 is a back elevational view of the seal device of FIG. 1 takenalong line VII—VII of FIG. 2, showing the seal device employed with arotating shaft.

FIG. 8 is a partial cross sectional side view of a seal deviceconstructed in accordance with a sixth preferred embodiment of thepresent invention.

FIG. 9 is a partial cross sectional side view of a seal deviceconstructed in accordance with a seventh preferred embodiment of thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIGS. 1, 2 and 7, a labyrinth seal 100 is shown havinga rotor 11 affixed to a rotatable shaft 14 via an O-ring 12. Thelabyrinth seal provides an obstructed, or mazelike, passageway betweenat least two components, and which provides dynamic and static sealingthrough an arrangement whereby the static component of the device doesnot contact, or contacts only inconsequentially, the rotating componentof the device and the rotating shaft about which the rotating componentis mounted. The contact is so slight that it will not result inunacceptable damage to the seal or the rotating shaft.

A stator 16 is affixed to a stationary housing 26 via an O-ring 22. Therotor 11 includes alternating annular ridges 60, 62, 64, 66 and annulargrooves 61, 63, 65. As shown, the annular groove 65 extends radiallyinward farther than the groove 63, which itself extends radially inwardfarther than the groove 61.

The stator 16 includes a cover portion 18 and a main portion 20. Withinthe cover portion 18 is an air-side opening 30, a radially inwardprotrusion 70, and a cover shoulder 80 which abuts the housing 26. Themain portion 20 includes an annular ridge 72 having an air side facingsurface 34, a second annular ridge 24 through which an axial groove 36extends, a stator flange 38 having an end face 28, and an oil-sideopening 32, having two open ends 32 a, 32 b. The main portion 20 of thestator 16 completely encircles the rotating shaft 14. Specifically, thestator flange 38 extends around the entire circumference of the shaft 14without an opening in the end face 28. In this way, the stator 16 isadapted to completely surround the shaft 14.

The stator 16 interlocks with the rotor 11 to create the two-piece,interlocked labyrinth seal 100. Specifically, the annular protrusion 70fits within the annular groove 61 and the surfaces 34, 40 face oneanother with a narrow gap therebetween. This arrangement allows therotor 11 to rotate with the shaft 14 and relative to the stator 16 andthe housing 26 with no more than inconsequential contact between therotor 11 and the stator 16.

The rotor 11 is preferably interlocked with the stator 16 prior tomounting onto the shaft 14. The stator 16 is assembled with the rotor 11by either thermally contracting or expanding one of the pieces, such asexpanding the stator 16, mechanically expanding the stator 16 relativeto the rotor 11 by, for example, snapping together the stator 16 and therotor 11 or by pushing the stator 16 over the rotor 11. Alternatively, acombination of these two methods, or another suitable interlockingmechanism may be used. In operation, the rotor 11 rotates with the shaft14 and relative to the stator 16. The seal 100 is positioned about theshaft 14 between an air side A and an oil side B located within thehousing 26.

A narrow gap 82 is provided between the rotor 11 and the stator 16. Thelengths of the ridges 60, 62, 64, 66 and the depths and widths of thegrooves 61, 63, 65 may be such that the contaminants entering the seal100 from the air-side A through the gap 82 are sufficiently slowed toallow some or all of the contaminants to drop out of the seal 100 bygravity through the air-side opening 30. In operation, contaminantsmaking their way through the groove 61 are flung radially outwardly intothe space radially outward of the ridges 62, 64, 66. The varying widthsof the grooves 61, 63, 65 assist in controlling the speed of thecontaminants. The narrower the width, the greater the speed of thecontaminants through that groove. The greater the width, the slower thespeed of the contaminants. The relatively wide space radially outward ofthe ridges 62, 64, 66 and the grooves 63, 65 allows the speed of thecontaminants to drop, such that the contaminants contact an innersurface 19 of the cover 18 and exit the seal 100 through the air-sideopening 30.

In certain applications, such as, for example, in side-mounted pumpbearing frames having double row thrust bearings in which the seals areclose to the bearings, oil on the oil side B splashes up severely. Toinhibit leakage during such severe splashes, the illustrated device hasthe flange 38 and the oil-side opening 32 positioned on the stator mainportion 20. The flange 38 is positioned relative to the shaft 14 so asto hinder movement of oil from the oil side B into the interior of theseal 100. Specifically, in the embodiment shown, the annular tip 39 ofthe flange 38 may be positioned about 0.02 inches from the shaft 14 fortypical oil applications. This tolerance may be varied depending uponthe viscosity of the oil, the rotational speed of the shaft 14, thetemperature within the housing 26, or other factors. If the flange 38 isformed of a material which will not unacceptably damage the shaft 14,such as, for example, polytetrafluoroethylene (PTFE), the flange 38 canbe allowed to contact the shaft 14 in some applications. Furthermore,the flange 38 is provided without any opening in its end face 28. Thus,oil is hindered from migrating from the oil side B since the potentialpathways for such a migration may only be through the clearance betweenthe tip of the flange 38 and the shaft 14 or through the open end 32 bof the oil-side opening 32.

During certain severe splash applications, oil may nevertheless migratefrom the oil side B past the flange 38 and into the interior of the seal100. The oil-side opening 32 open end 32 b is positioned radiallyoutward of the open end 32 a, and the direction between the open ends 32a, 32 b is transverse, and may be generally perpendicular, to the shaft14. The oil-side opening 32 provides a return egress to allow oil whichhas splashed up axially beyond the flange 38 to return to an oilreservoir positioned on the oil side B. The opening 32 extends throughthe main portion 20 of the stator 16 and exits at open end 32 b oppositean underside surface 27 of the housing 26. Any oil that migrates intothe interior of the seal 100 is flung radially outwardly by the rotatingshaft 14. The combination of the rotating shaft 14, the annular ridges72, 24, and the axial groove 36 direct oil in the interior of the seal100 back toward the oil-side opening 32, and from there by gravity backto the oil side B.

Furthermore, the positioning of the open ends 32 a, 32 b of the oil-sideopening 32 and the flange 38 are such as to inhibit oil from migratingfrom the oil side B, through the axial groove 36, and into the interiorof the seal 100. Such an arrangement assists, in applications wheresplashing of oil is of concern, in hindering oil from splashing from theoil side B into the interior of the seal 100.

A second preferred embodiment is illustrated in FIG. 3. Specifically, atwo-piece, interlocked labyrinth seal 200 is shown having a rotor 11 anda stator 116. The stator 116 includes the cover 18 and a main portion120 having an oil-side opening 132. The main portion 120 differs fromthe main portion 20 shown in FIG. 2 in that the opening 132 is shorterthan the opening 32. Moreover, the opening 132 shown in FIG. 2 exitsonto an undersurface 42 on the main portion 120 instead of the undersidesurface 27 of the housing 26. A shortened opening 132 allows for ashorter return egress for the oil back to the oil side B. As with theembodiment illustrated in FIGS. 1 and, 2, the embodiment shown in FIG. 3includes the annular tip 39 of a flange 138. The tip 39 is annular andis close to or in contact with the entire periphery of the shaft 14.

A third preferred embodiment is illustrated in FIG. 4. Specifically, atwo-piece, interlocked labyrinth seal 300 is shown having a rotor 111and a stator 216. The rotor 111 differs from the rotor 11 (FIGS. 1-3) inthat it includes a radially outwardly facing recess 148 between ridge 66and a flange 146. The flange 146 acts as a slinger to direct oil backtoward axial groove 36 and, ultimately, the oil side B. The stator 216has a main portion 220 having an annular ridge 172 and an annular ridge124. The annular ridge 124 includes a ledge 144. The annular ridge 172differs from the annular ridge 72 in that it has a sloped surface to fitwithin the recess 148. The ridge 124 differs from the ridge 24 in thatit is longer and it includes the ledge 144. The annular ridge 124 andthe ledge 144 provide room for the axial groove 136 to extend to theflange 38. As with the previous embodiments, the embodiment shown inFIG. 4 has the annular tip 39 of the flange 38. The tip 39 is annularand is close to or in contact with the entire periphery of the shaft 14.

A fourth preferred embodiment is illustrated in FIG. 5. Specifically, atwo-piece, interlocked labyrinth seal 400 is shown having a rotor 111and a stator 316. The stator 316 includes a main portion 320 having anannular ridge 224 and an oil-side opening 232. The ridge 224 is longerthan the ridge 24. The opening 232 is shorter than the opening 132 (FIG.2). As with the previous embodiments, the embodiment shown in FIG. 5includes the annular tip 39 of the flange 138. The tip 39 is annular andis close to or in contact with the entire periphery of the shaft 14.

A fifth preferred embodiment is illustrated in FIG. 6. Specifically, atwo-piece, interlocked labyrinth seal 500 is shown having a rotor 11 anda stator 416. The stator 416 includes the cover 18 and a main portion420 having an oil-side opening 332 and a flange 238. The main portion420 differs from the main portion 20 shown in FIG. 2 in that the opening332 and the flange 238 are shorter than the opening 32 and the flange38, creating a larger distance between the opening 332 and the undersidesurface 27 of the housing 26. The greater distance between the opening332 and the underside surface 27 of the housing 26 helps to inhibit oilreturning through the opening 332 from splashing into the undersidesurface 27 and reentering the opening 332. The main portion 420 shown inFIG. 6 differs from the main portion 120 of FIG. 3 in that the opening332 is longer than the opening 132. In addition, the opening 332 exitsto the underside surface 27 of the housing 26 instead of on theundersurface 42 of the main portion 120 of FIG. 3. As with theembodiments described above, the embodiment shown in FIG. 6 includes theannular tip 39 of the flange 238. The tip 39 is annular and is close toor in contact with the entire periphery of the shaft 14.

FIG. 8 illustrates a wrap-around severe splash seal 600 mounted on thehousing 26 and the rotating shaft 14. The seal 600 includes a stator 620and a rotor 611. The stator 620 has a main body portion 622 and a cover644. The main body portion 622 includes three annular ridges 626, 630,638 extending inwardly toward the shaft 14 and a flange 634. The flange634 serves as a shoulder for mounting the seal 600 on the housing 26.

The ridges 630 and 638 each extend toward the shaft 14 a smallerdistance than the ridge 626. Specifically, the ridges 630 and 638 eachhave a small gap between themselves and the shaft 14 when the seal 600is properly installed. The ridge 630 further includes an opening 624 toallow oil to return to the oil side B through an opening 632 in thestator body portion 622. The middle ridge 630 is optional. The ridge 626is adjacent to the rotor 611 and is formed to be about shaft size, suchthat upon installation of the seal 600 on the shaft 14, the ridge 626contacts the shaft 14 and restrict air flow. Alternatively, the ridge626 may not contact the shaft 14 but may extend toward the shaft 14 toleave a gap smaller than the gap between the ridges 630, 638 and theshaft. The ridge 626 is thin, and so if it contacts the shaft 14 it willdeform to the shaft without binding. Air flow may carry oil mist, andthus the ridge 626 assists in restricting the migration of oil from theoil side B to the air side A. During use, the inside diameter of theridge 626 will alter to become the size of the circle created by therotating shaft 14, including any shaft wobble.

The rotor 611 includes an intermediate portion 652 and an enclosuremember 654 which extend around and define a radial opening 640. Thecover 644 extends into the radial opening 640, and the enclosure member654 interlocks with the cover 644 within the radial opening 640. Wheninterlocked, an inwardly directed end face 656 of the enclosure member654 is directly adjacent to an outwardly directed flange face 658 of theflange 634.

An alternative wrap-around severe splash seal is illustrated in FIG. 9.The severe splash seal 700 includes a rotor 711 interlocked with astator 720. The stator 720 has a main body portion 722 and a cover 744.The main body portion 722 includes three annular ridges 726, 730, 738extending inwardly toward the shaft 14 and a flange 734 which serves asa shoulder for mounting the seal 700 on the housing 26.

The ridges 726, 730 and 638 each extend toward the shaft 14 and leave asmall gap between themselves and the shaft 14 when the seal 700 isproperly installed. The ridge 730 further includes an opening 724 toallow oil to return to the oil side B through an opening 732 in thestator body portion 722. The middle ridge 630 is optional. The cover 744includes an interlocking portion 746, through which extends a radialopening 745. As illustrated, the cover 744 further includes a pair offlanges 747, 749 which assist in moving contaminants out of the seal700.

The rotor 711 includes an intermediate portion 752, an enclosure member754 and a flange 715, all of which extend around and define a radialopening 740. The cover 744 extends into the radial opening 740, and theinterlocking portion 746 interlocks with the flange 715 within theradial opening 740. The enclosure member 754 is radially outside of theinterlocking between the interlocking portion 746 and the flange 715.When interlocked, an inwardly directed end face 756 of the enclosuremember 754 is directly adjacent to an outwardly directed flange face 758of the flange 734.

The above description and drawings are only illustrative of certainpreferred versions which achieve the objects, features and advantages ofthe present invention. It is not intended that the present invention belimited to these versions. For example, although two-piece seals areillustrated and described, the present invention is not to be so limitedand can include seals with a different number of pieces. Further,although the seals illustrated and described include pieces whichinterlock one with the other, the present invention is not to be solimited and can include seals having separate pieces which do notinterlock. In addition, while the direction between the open ends 32 a,32 b is illustrated to be generally perpendicular to the shaft 14, it isto be understood that either of the ends 32 a, 32 b may be positionedcloser to the oil side B than the other of the ends 32 a, 32 b. Also,while the flange 38 is described as part of the stator, it is to beunderstood that the flange 38 could instead be located on the rotor 11.Further, the rotor 11 can be any other suitable shape. For example,although the rotor 11 is shown to be radially interior to the cover 18of the stator 16, the rotor 11 may instead extend radially outward ofand wrap around the cover 18. In addition, while a rotating shaft isdescribed, a rotating bore may be used instead by making a few minoradjustments, such as, for example, adding additional oil-side openings32 to the stator, or, for the embodiment illustrated in FIG. 9, addingan air-side opening in the enclosure member 754.

What is claimed as new and desired to be protected by Letters Patent of the United States is:
 1. A two-piece interlocked labyrinth seal, comprising: a rotor including an intermediate portion and an enclosure member surrounding a radial opening; and a stator including a main body portion, having three annular ridges, and a cover positioned within said radial opening, wherein said cover interlocks with said enclosure member, and wherein one of said annular ridges is adapted to restrict passage of air through the seal when the seal is mounted to a shaft, wherein two of said annular ridges extend a first distance and a third of said annular ridges extends a second distance, wherein said second distance is greater than said first distance.
 2. The labyrinth seal of claim 1, wherein said stator comprises a flange which with said intermediate portion and said enclosure member encloses said cover within said radial opening.
 3. The labyrinth seal of claim 1, wherein said third of said annular ridges inhibits passage of air through the seal when the seal is mounted to a shaft.
 4. The labyrinth seal of claim 1, wherein one of said annular ridges includes an opening.
 5. A two-piece interlocked labyrinth seal, comprising: a rotor including an intermediate portion, an enclosure member and a flange surrounding a radial opening; and a stator including a main body portion, having three annular ridges, and a cover positioned within said radial opening, wherein said cover interlocks with said flange, wherein two of said annular ridges extend a first distance and a third of said annular ridges extends a second distance, wherein said second distance is greater than said first distance and is sufficient to restrict passage of air through the seal.
 6. The labyrinth seal of claim 5, wherein said stator comprises a flange which with said intermediate portion, said enclosure member and said flange of said rotor encloses said cover within said radial opening.
 7. The labyrinth seal of claim 5, wherein said third of said annular ridges inhibits passage of air through the seal when the seal is mounted to a shaft.
 8. The labyrinth seal of claim 5, wherein one of said annular ridges includes an opening.
 9. The labyrinth seal of claim 5, wherein said cover includes an interlocking portion which interlocks with said flange.
 10. The labyrinth seal of claim 9, wherein a radial opening extends through said interlocking portion.
 11. The labyrinth seal of claim 10, wherein said interlocking portion includes a plurality of radially outwardly extending flanges.
 12. A sealed system, comprising: a rotatable shaft; a housing; and a two-piece interlocked labyrinth seal mounted on said housing and around said shaft, said seal comprising: a rotor including an intermediate portion and an enclosure member surrounding a radial opening; and a stator including a main body portion, having three annular ridges, and a cover positioned within said radial opening, wherein said cover interlocks with said enclosure member, and wherein one of said annular restricts passage of air between the seal and said rotatable shaft, wherein two of said annular ridges extend a first distance and a third of said annular ridges extends a second distance, wherein said second distance is greater than said first distance.
 13. The sealed system of claim 12, wherein said stator comprises a flange which with said intermediate portion and said enclosure member encloses said cover within said radial opening.
 14. The sealed system of claim 12, wherein said third of said annular ridges inhibits passage of air through the seal when the seal is mounted to a shaft.
 15. The sealed system of claim 14, wherein said third annular ridge contacts said shaft when said seal is mounted on said housing and around said shaft.
 16. The sealed system of claim 12, wherein one of said annular ridges includes an opening.
 17. A sealed system, comprising: a rotatable shaft; a housing; and a two-piece interlocked labyrinth seal mounted on said housing and around said shaft, said seal comprising: a rotor including an intermediate portion, an enclosure member and a flange surrounding a radial opening; and a stator including a main body portion, having three annular ridges, and a cover positioned within said radial opening, wherein said cover interlocks with said flange, wherein two of said annular ridges extend a first distance and a third of said annular ridges extends a second distance, wherein said second distance is greater than said first distance and is sufficient to restrict passage of air between the seal and the rotatable shaft.
 18. The sealed system of claim 17, wherein said stator comprises a flange which with said intermediate portion and said enclosure member encloses said cover within said radial opening.
 19. The sealed system of claim 17, wherein said third of said annular ridges inhibits passage of air through the seal when the seal is mounted to a shaft.
 20. The sealed system of claim 19, wherein said third annular ridge contacts said shaft when said seal is mounted on said housing and around said shaft.
 21. The sealed system of claim 17, wherein one of said annular ridges includes an opening. 